Recent in situ measurements have led to a substantial revision of our picture of the magnetosphere and parts of the heliosphere. This concerns the character and distribution of electric fields and currents, the ways in which charged particles are energised, and the chemical composition of the magnetospheric plasma. This revision reflects the fact that real cosmic plasmas behave in fundamentally different ways than predicted by the traditional, idealised models used in magnetospheric physics and in astrophysics. The new understanding of the general properties of cosmic plasma gives us an improved basis on which to interpret astrophysical observations.